textproduct: Quad Cities

KEY MESSAGES

- Active pattern this week to bring numerous rounds of showers and storms with heavy rain possible.

- There is a Marginal Risk, Level 1 out of 5, for severe storms north of I-80 Monday evening into the overnight hours. Primary hazards will be heavy rain and damaging winds.

- An elevated flash flood risk may develop mid-week with repeating rounds of storms. Rainfall totals over 2 inches are likely (60-80%), with localized areas of 5+ inches possible (10-20%), leading to rises on area creeks and streams.

SHORT TERM /THROUGH TUESDAY/

Issued at 131 AM CDT Sun Sep 13 2026

After a mostly dry Saturday, scattered showers (30-60% coverage) return this morning as confluent flow in the mid- levels support an F-gen band on the backside of a stationary front over northern Missouri. Northerly flow forced by a high pressure over Minnesota will keep high temperatures below average in the upper 60s and low 70s. Heading into the evening, conditions dry out again, but this will not last long with a longwave ridge over the Mid-to-Upper Mississippi River Valley introducing southwesterly flow in the 850-to-500 mb layer and converting the stationary front into a warm front.

On Monday, more scattered showers and storms (30-50% coverage) will fire along the warm front as it is pulled northward by a developing low pressure center over the Northern Plains. These storms are expected to be elevated and could tap into 1000-1500 J/kg of MUCAPE and 40+ knots of 0-6-km shear. While the overall severe potential is low (less than 5%) with this morning round, isolated hail cannot be ruled out with the strongest cells. By the late afternoon and early evening, another period of dry conditions is expected ahead of the approaching cold front and shortwave trough, but a strong LLJ over eastern Iowa may support surface wind gusts up to 30 knots during this time.

Overnight Monday, a closed heights center positioned over the Northern Rockies negatively tilts as it lifts into south-central Canada. Widespread showers and storms (80-100% coverage) are expected along the cold front moving in from the northwest, but lackluster mid-level lapse rates will put a hamper on the overall instability (750-1500 J/kg of SBCAPE). This is forecasted to, once again, limit the overall severe potential. However, there is a brief window where a mid-level jet boosts the 0-6-km shear along the front to 45+ knots north of I-80. The SPC has maintained a Marginal Risk, Level 1 out of 5, for severe storms with primary hazard being damaging winds. By Tuesday, storm coverage and instability decreases as upper- level dynamical support weakens. The cold front is forecast to stall out over northern Missouri, similar to today's set up, keeping storm chances around through the end of the week.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Issued at 131 AM CDT Sun Sep 13 2026

The second half of the week is going to remain stormy. A ridge over the Southeast and a slow-moving shortwave trough over the western CONUS is forecast to pull multiple, weak subtropical troughs northeastward into the Midwest. With the stationary front from Tuesday's system acting as the source of lift, scattered showers and storms will likely develop daily. With saturated grounds expected after the rounds of rain today through Tuesday, the flood threat will become more elevated with each subsequent round. The WPC already has a Slight Risk, Level 2 out of 4, for excessive rainfall Monday night into Tuesday, and another areawide Slight Risk for Wednesday. In terms of rainfall totals, latest LREF guidance has a 60-80% of 2+ inches across eastern Iowa and 30-50% across northwest Illinois and northeast Missouri through Saturday. There is a lot of uncertainty though in the axis (or axes) of heaviest rainfall with the LREF 10th-90th percentile spread showing a 2-3 inch difference areawide. Therefore, while the probabilities are low (10-20%) for 5+ inches of rainfall across eastern Iowa, the ensemble spread is suggesting that latest model guidance may be the undercutting the high-end totals.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1230 PM CDT Sun Sep 13 2026

Scattered showers are expected across eastern Iowa into northwest Illinois through this afternoon, which may result in brief periods of MVFR visibilities. Ceilings should remain mainly at VFR, holding between 5000-9000 ft AGL. Quiet conditions and prevailing VFR are expected for tonight into early Monday AM, along with light winds. Another round of showers and isolated storms are possible later Monday AM, but will not include in the TAFs yet due to lower confidence this far out.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.